JP2000311934A - Wafer support member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the situation, where at 100 deg.C or above, silver ions and copper ions of solder, which joints a plate-like ceramics to an external terminal connected to an internal electrode acting as an electrostatic attraction electrode or plasma generating electrode, migrate for conduction between external terminals, thus losing electrostatic attraction or a plasma. SOLUTION: External terminals 5 and 6 electrically connected to internal electrodes 3 and 4 working as an electrostatic attraction electrode or plasma generating electrode, which are embedded in plate-like ceramics 2 comprising a placement surface 2a for a wafer W are planted in the plate-like ceramics 2 using solder comprising silver and/or copper, and cylindrical bodies 7a and 8 whose thermal expansion factor is larger than the external terminals 5 and 6 are attached to the outer periphery of the external terminal 5 and 6, while the end part of the cylindrical body 7 and 8 is set away from the surface of the plate-like ceramics 2 by prescribed distance (t), constituting a wafer support member 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer supporting member such as an electrostatic chuck or a susceptor for supporting a wafer in a high-temperature atmosphere, and more particularly to a process for manufacturing a semiconductor device or a liquid crystal, such as PVD or CVD, in a manufacturing process. It is suitable for a film device or an etching device.

[0002]

2. Description of the Related Art Conventionally, in the manufacturing process of a semiconductor device,
PV for forming a film on a semiconductor wafer (hereinafter, referred to as a wafer)
2. Description of the Related Art A film supporting device such as an electrostatic chuck or a susceptor for supporting a wafer is used in a film forming device such as a CVD process or a dry etching device for performing a fine etching process on a wafer.

For example, a wafer support member 31 shown in FIGS. 5 (a) and 5 (b) is a so-called electrostatic chuck, which is made up of a disc-shaped plate-like ceramic body 32, and has an upper surface on which a wafer W is placed. In the plate-shaped ceramic body 32, in order from the mounting surface 32 a side, one disk-shaped internal electrode 33 as a plasma generation electrode and two half-electrodes as an electrostatic attraction electrode are arranged. Each of the circular internal electrodes 34 is embedded, and these internal electrodes 33 and 34 are embedded.
Is a pilot hole 32b opening on the lower surface of the plate-like ceramic body 32.
In addition, there has been a device electrically connected to metal external terminals 35 and 36 joined by using a brazing material mainly composed of silver (Ag) and / or copper (Cu) (JP-A-11-7411).
336).

[0004] Incidentally, reference numeral 41 shown in FIG. 5 (b) denotes another plasma generation electrode paired with the plasma generation electrode provided on the wafer support member 31.
Plasma was generated by applying high-frequency power between 3, 41.

In order to hold the wafer W by the wafer support member 31, after the wafer W is mounted on the mounting surface 32a, a current is applied between the external terminals 36 to cause a Coulomb force due to dielectric polarization or a minute leakage current. In such a case, the wafer W is attracted and fixed on the mounting surface 32a by expressing electrostatic attraction force such as Johnson-Rahbek force.

In FIGS. 5A and 5B, the internal electrodes 3
3 shows an example of the wafer support member 31 provided with an electrode for plasma generation and an electrode for electrostatic attraction as the internal electrode 34, but other than this, a wafer support member called a susceptor provided with an electrode for heater as an internal electrode Or a wafer support member provided with a heater electrode and a plasma generation electrode, or an electrostatic suction electrode and a heater electrode, and a three-electrode of an electrostatic suction electrode, a plasma generation electrode, and a heater electrode.
There are also wafer support members with two internal electrodes.Each internal electrode comes to be electrically connected to external terminals joined to a plate-shaped ceramic body with a brazing material mainly composed of silver or copper. I was

[0007]

By the way, in order to perform the film forming process on the wafer W, the wafer W is set at a processing temperature of 100 ° C.
The wafer support member 31 shown in FIG. 5 needs to be heated to a high temperature of 100 ° C. or higher, and may be heated to a high temperature of 100 ° C. or higher in the etching process. Cycles will be added.

However, when a DC voltage is continuously applied between the external terminals 36 in order to develop an electrostatic attraction force in such a high temperature atmosphere, the external terminals 36 are connected to the plate-like ceramic body 32.
There is a problem that silver ions and copper ions, which are constituent components of the brazing material to be bonded, cause migration, and silver ions and copper ions move from the anode side to the cathode side. Specifically, when a DC voltage of 250 V is applied between the external terminals 36, it takes about 10 minutes when the distance between the external terminals 36 is about 10 mm, and about 30 seconds when the distance between the external terminals 36 is about 5 mm. Migration occurred.

If the migration leads to conduction between the external terminals 36 and the insulation cannot be maintained, there is a problem that the electrostatic chucking force cannot be developed and the device cannot function as an electrostatic chuck.

The problem of the migration is that the external terminal 35 electrically connected to the internal electrode 33 forming the electrode for plasma generation and the internal electrode 3 forming the electrode for electrostatic adsorption.
4 and the external terminal 36 electrically connected, and if the insulation between the two could not be maintained, plasma could not be generated.

On the other hand, as a method for preventing such migration, a brazing material layer forming a joint between the external terminals 35 and 36 and the plate-like ceramic body 32 is covered with an insulating resin film or a nickel film. Although it is conceivable to use a brazing material that does not contain silver or copper, which easily causes ion migration, as a brazing material, the method of coating a resin film cannot be used because the heat resistance temperature is too low, and a nickel film is coated. In this method, there is a disadvantage that the nickel film is peeled off due to a large difference in thermal expansion from the plate-shaped ceramic body 32. In the case of using a brazing material containing no silver or copper, the brazing temperature is high and the brazing temperature is high. Due to the high rigidity of the material, the stress generated at the joint cannot be reduced, and the plate-shaped ceramic body 3
Neither of them was practically usable, as there was a risk of damaging the No. 2.

[0012]

SUMMARY OF THE INVENTION In view of the above problems, the present invention has at least one internal electrode in a plate-like ceramic body having a mounting surface on which a wafer is mounted. In a wafer supporting member in which an external terminal to be electrically connected is implanted in the plate-shaped ceramic body using a brazing material containing silver and / or copper, an outer periphery of the external terminal may be arranged more than the external terminal. A cylindrical body made of a metal member coated with ceramic having a large thermal expansion coefficient, Ni or a Ni alloy, or one of Ni, Au, and Pt is attached, and an end of the cylindrical body is attached to the plate-shaped ceramic. It is characterized by being arranged at a position separated from the surface of the body by a predetermined distance.

The present invention also provides an annular groove formed on a surface of the plate-shaped ceramic body at a position where an end of the cylindrical body is opposed, and the end of the cylindrical body is made to extend from the bottom of the annular groove. It is characterized by being arranged at a position separated by a predetermined distance.

Further, according to the present invention, as the internal electrode,
It is used as an electrode for electrostatic attraction, an electrode for a heater, and an electrode for plasma generation.

In the present invention, the predetermined distance means that in a high-temperature atmosphere, the cylindrical body thermally expands more than the external terminals and abuts on the surface of the plate-shaped ceramic body, and the external body is pressed by the cylindrical body. It refers to the distance that the terminal can be brought into close contact with the plate-shaped ceramic body so as not to come off. The high-temperature atmosphere refers to a processing temperature of 100 ° C. or more at which a film is formed or etched on a wafer.
The heating means includes heating the wafer support member directly or indirectly heating the wafer support member.

[0016]

According to the wafer support member of the present invention, silver and / or copper are electrically connected to the internal electrodes forming the electrodes for electrostatic attraction, the electrodes for the heater, and the electrodes for plasma generation. A cylindrical body having a larger coefficient of thermal expansion than the external terminal is attached to the outer periphery of the external terminal joined by the brazing material containing, and the end of the cylindrical body is attached to the surface of the plate-shaped ceramic body. Provided at a position further separated by a predetermined distance, and 100
In a high-temperature atmosphere of ℃ or higher, the cylindrical body is expanded more thermally than the external terminals so that it adheres tightly to the plate-shaped ceramic body. Accordingly, even if silver ions or copper ions of the brazing material that joins the external terminals cause migration, the movement can be prevented and confined by the cylindrical body, so that the external terminals do not conduct with each other and have an insulating property. Can be kept.

Therefore, if the wafer support member of the present invention is used, an electrode for electrostatic attraction embedded in a plate-like ceramic body,
It is possible to stably supply current to the heater electrode and the internal electrode serving as the plasma generation electrode.

Further, at room temperature, since the end of the cylindrical body is separated from the surface of the plate-shaped ceramic body, even if the cylindrical body adheres to the surface of the plate-shaped ceramic body in a high-temperature atmosphere, It is possible to prevent a tensile stress greater than the brazing strength from acting on the brazing portion of the external terminal, thereby preventing the external terminal from coming off.

Further, the cylindrical body is made of ceramic, Ni
Or a metal member coated with any one of Ni alloy, Ni, Au and Pt, thereby preventing corrosion of the brazing material layer and external terminals even when exposed to corrosive halogen gas or plasma. be able to.

According to the present invention, an annular groove is formed on the surface of the plate-shaped ceramic body at a position where an end of the cylindrical body is opposed, and an end of the cylindrical body is connected to the annular groove. Since it is installed at a position separated by a predetermined distance from the bottom surface, the contact area between the plate-shaped ceramic body and the cylindrical body can be increased and the airtightness can be increased, so that the progress of migration can be effectively prevented and In addition, corrosion of the brazing material layer and external terminals from corrosive gas such as halogen gas or plasma can be effectively prevented.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail.

FIG. 1A is a perspective view showing an example of the wafer supporting member of the present invention, FIG. 1B is a sectional view taken along line XX of FIG. 1A, and FIG. 2A is FIG. 1 (b) is a cross-sectional view of a main part of FIG. 1 (b) under a high-temperature atmosphere, in which the main part is enlarged.

The wafer support member 1 is called an electrostatic chuck, and is made of a disk-shaped plate-shaped ceramic body 2 whose upper surface is used as a mounting surface 2a for the wafer W. In order from the mounting surface 2a side,
An inner electrode 3 as a disk-shaped electrode for plasma generation and an inner electrode 4 as an electrode for electrostatic attraction are buried, and these inner electrodes 3 and 4 are opened on the lower surface of the plate-shaped ceramic body 2. The metal external terminals 5 and 6 are electrically connected to the prepared hole 2b using a brazing material mainly composed of silver (Ag) and / or copper (Cu).

In FIG. 1B, reference numeral 41 denotes another plasma-generating electrode paired with the internal electrode 3 provided on the wafer support member 1, and high-frequency power is applied between these electrodes 3 and 41. By doing so, plasma is generated.

As shown in FIG. 3 (a), the internal electrode 4 buried in the plate-shaped ceramic body 2 is formed by arranging two semicircular electrodes 4a so as to form a circle. Electrode 4
By making the outermost diameter substantially equal to or slightly larger than the outer diameter of the wafer W, the entire surface of the wafer W can be uniformly attracted and fixed.

As the pattern shape of the internal electrode 4 forming the electrode for electrostatic attraction, in addition to the pattern shape shown in FIG. 3A, for example, a fan-shaped electrode 4a as shown in FIG.
The wafer W can be fixed with a uniform suction force over substantially the entire surface of the wafer W, such as an arrangement in which the electrodes are arranged in a circle or an arrangement in which the ring-shaped electrodes 4a are arranged concentrically as shown in FIG. Any pattern shape may be used.

Also, the outermost diameter of the internal electrode 3 serving as a plasma generating electrode is made substantially equal to or slightly larger than the outer diameter of the wafer W in order to generate a plasma having a uniform density over the entire surface of the wafer W. Good. The form of the internal electrodes 3 and 4 may be any form such as a film, a mesh, or a foil.

Further, on the outer periphery of the external terminals 5 and 6,
As shown in (a), the cylindrical body 8 made of ceramics, Ni or Ni alloy, or a metal member coated with Ni, Au, or Pt having a larger thermal expansion coefficient than the external terminals 6 and (5). (7) attached, cylindrical body 8, (7)
In a high-temperature atmosphere in which processes such as film formation and etching are performed, as shown in FIG.
The cylindrical body 8,
The end of (7) is separated from the lower surface of the plate-shaped ceramic body 2 by a distance t such that the end is airtightly adhered.

It is to be noted that that the ends of the cylindrical bodies 8 and (7) are separated from the lower surface of the plate-shaped ceramic body 2
It is not necessary that the entire end of (7) is separated from the lower surface of the plate-shaped ceramic body 2, and the end may be partially in contact with the plate-shaped ceramic body 2.

When the end portions of the cylindrical bodies 8 and (7) are separated from the lower surface of the plate-shaped ceramic body 2 by a predetermined distance, screw portions 6a (5a) provided on the outer periphery of the external terminals 6 and (5)
The threaded portion 8a provided on the inner periphery of the cylindrical body 8, (7) is screwed together, and the distance t is controlled by adjusting the screw feed amount.

In order to adsorb and fix the wafer W by the wafer support member 1, a DC voltage is applied between the external terminals 6 while the wafer W is mounted on the mounting surface 2a, and the Coulomb force due to the dielectric polarization or the like is reduced. Johnson leakage due to small leakage current
The wafer W can be suction-fixed on the mounting surface 2a by expressing electrostatic adsorption force such as Rabbeck force. In this state, the wafer support member 1 is indirectly heated by a heater, a lamp, or the like, and By supplying the positioning gas and the etching gas, the film formation processing and the etching processing with high accuracy can be performed on the wafer W.

At this time, the wafer support member 1 is heated by a heater, a lamp, or the like, so that silver ions and copper ions, which are constituent components of the brazing material for joining the external terminals 6, cause migration, so that the anode side changes to the cathode side. As shown in FIG. 2B, the cylindrical body 8 attached to the outer periphery of the external terminal 6 moves under the high temperature atmosphere. 6 and one end of the external terminal 6 is brazed and fixed to the plate-shaped ceramic body 2, so that the external terminal 6 is air-tightly adhered to the surface of the plate-shaped ceramic body 2, and the movement of silver ions and copper ions is reduced. Shape 8
And the conduction with the external terminal 6 on the cathode side can be prevented.

In the migration, an external terminal 5 electrically connected to the internal electrode 3 serving as an electrode for plasma generation, and an external terminal 6 electrically connected to the internal electrode 4 serving as an electrode for electrostatic attraction. 2A, the movement of silver ions and copper ions is confined in the cylindrical body 7 because the cylindrical body 7 shown in FIG. , Conduction between the two can be prevented.

As described above, according to the present invention, even when silver ions and copper ions of the brazing material joining the external terminals 5 and 6 migrate due to the wafer support member 1 being exposed to a high-temperature atmosphere. Since the insulation between the external terminals 5 and 6 can be maintained, stable electrostatic attraction force and uniform plasma can be generated for a long period of time, and the wafer support member 1 having a long life can be obtained. it can.

However, from the viewpoint of enhancing the airtightness when the ends of the cylindrical bodies 7 and 8 come into contact with the lower surface of the plate-shaped ceramic body 2, each of the cylindrical bodies 7 and 8 and the plate-shaped ceramic body 2 Is 0.01 to 0.8 μm in center line average roughness (Ra).
It is preferable to finish the surface accuracy.

Further, depending on the structure of the film forming apparatus or the etching apparatus, the external terminals 5 and 6 of the wafer support member 1 may be exposed to a halogen gas in a deposition gas or an etching gas, or to plasma. However, according to the present invention, the external terminals 5 are formed by the cylindrical members 7 and 8 made of ceramics, Ni or Ni alloy, or a metal member coated with any of Ni, Au, and Pt having high corrosion resistance and plasma resistance. , 6 are covered, so that the corrosive wear of the brazing material layer 9 for joining the external terminals 5, 6 and the external terminals 5, 6 can be suppressed.

2 (a) and 2 (b), the cylindrical member 8,
As a means for attaching (7) to the outer periphery of the external terminals 6 and (5), the means by screwing has been described. However, the processing temperature and the cylindrical members 8 and (7) and the external terminals 6 and (5) are previously determined. In consideration of the degree of thermal expansion, the tubular members 8 and (7) may be integrally joined to the outer periphery of the external terminals 6 and (5).

Incidentally, such a plate-like ceramic body 2
As a material for forming, a material excellent in abrasion resistance, heat resistance, thermal shock resistance, plasma resistance, and corrosion resistance is good, and ceramics mainly containing alumina, silicon nitride, sialon, aluminum nitride, and boron carbide are used. Among them, the content of alumina (A1 ₂ O ₃ ) is 99%.
% By weight or more, containing alumina ceramics containing sintering aids such as silica (SiO ₂ ), magnesia (MgO), and calcia (CaO) as other components, and aluminum nitride (AIN) as a main component. Aluminum nitride ceramics containing an oxide of a Group 2a or 3a element in the range of 0.5 to 10% by weight, or high-purity aluminum nitride having an aluminum nitride (AIN) content of 99.8% by weight or more The porous ceramics are excellent in plasma resistance under a halogen gas atmosphere used in a film forming apparatus and an etching apparatus, and are suitable.

As a material for forming the external terminals 5 and 6, a material having a thermal expansion coefficient close to that of the plate-like ceramic body 2 is preferable, and Mo (5.2 to 6.5 × 10 ⁻⁶ / ° C.) , Fe
-Ni alloy (5.0-5.5 × 10 ^-6 / ° C), Fe-C
An o-Ni alloy (4.5 to 5.0 × 10 ⁻⁶ / ° C.) can be used.

Further, as described above, the material of the cylindrical bodies 7 and 8 is ceramics, Ni or Ni alloy (10.0 to 10.0) having a larger thermal expansion coefficient than the external terminals 5 and 6.
14.0 × 10 ⁻⁶ / ° C.) or a metal member coated with any of Ni, Au, and Pt may be appropriately selected. As the ceramic, alumina ceramic (7.0 to 7.9 × 10 6) is used. ⁻⁶ / ° C.), aluminum nitride ceramics (4.2 to 5.5 × 10 ⁻⁶ / ° C.), boron carbide ceramics (4.0 to 4.5 × 10 ⁻⁶ / ° C.), and the like. it can. Further, as the shape of the tubular bodies 7 and 8, various cross-sectional shapes such as a polygon such as a circle, a square, and an ellipse can be adopted.

In order to manufacture the wafer supporting member 1 shown in FIGS. 1A and 1B, first, a binder and a solvent are added to the above-mentioned ceramic powder constituting the plate-shaped ceramic body 2. To form a plurality of ceramic green sheets by a tape forming method such as a doctor blade method. A conductor paste is printed on one of the ceramic green sheets in a disk shape, and another is formed. The conductor paste is printed on the ceramic green sheet in the pattern shape shown in FIG. 3A and then laminated, and the remaining ceramic green sheets are further laminated and laminated. Next, after the obtained ceramic laminate is cut into a disk shape, it is fired at a temperature at which each ceramic powder can be sintered, or the slurry is dried and granulated to produce granules, which are then uniaxially pressed. After forming a disk-shaped molded body by a press method or isopressing method, a conductor paste is printed in a pattern shape shown in FIG. 3A, or a foil having a pattern shape shown in FIG. After laying the board, filling it with granules, forming it by uniaxial pressing or isopressing, and then printing the conductor paste in a disk shape, or laying a disk-shaped foil plate The internal electrode 3 serving as an electrode for plasma generation is formed by filling the granules and molding by a uniaxial pressure molding method or an equal pressure molding method, and then firing at a temperature at which each ceramic powder can be sintered. And an internal electrode that forms the electrode for electrostatic adsorption The fabricating ceramic plate 2 formed by embedding.

Next, the main surface of the plate-like ceramic body 2 on the side where the internal electrodes 3 are embedded is polished to form a mounting surface 2a.
And a pilot hole 2b penetrating to the internal electrodes 3 and 4 is provided on the other main surface, and a metallizing process is performed in the pilot hole 2b, and then external terminals 5 having screw portions 5a and 6a on the outer periphery are formed. 6 is brazed and fixed using a brazing material mainly composed of silver or copper.

Then, the cylindrical members 7, 8 made of ceramics, Ni or Ni alloy, or a metal member coated with Ni or Pt having a larger thermal expansion coefficient than the external terminals 5, 6 are connected to the external terminals 5, 6. And the end portions of the cylindrical bodies 7 and 8 are set apart from the lower surface of the plate-shaped ceramic body 2 by a predetermined distance t. Specifically, when the thermal expansion difference between the external terminals 5 and 6 and the cylindrical bodies 7 and 8 is about 10 × 10 ⁻⁶ / ° C., the predetermined distance t may be provided in a range of 100 μm or less.

Thus, the wafer supporting member 1 shown in FIGS. 1A and 1B can be obtained.

Next, another embodiment of the present invention will be described with reference to FIG.

In this embodiment, an annular groove 2c is formed on the lower surface of the plate-like ceramic body 2 at a position facing the end of the tubular body 8, (7), and the end of the tubular body 8, (7) is formed. The part is the annular groove 2
It is installed at a predetermined distance t from the bottom surface of c. With such a structure, the contact area between the plate-shaped ceramic body 2 and the cylindrical bodies 8 and (7) can be increased, so that the airtightness can be further improved and the progress of migration can be prevented. What you can do, of course,
Corrosion of the brazing material layer 9 and the external terminals 6, (5) by corrosive gas such as halogen gas or plasma can be effectively prevented.

The present invention is not limited to the structure shown in FIGS. 2 and 4, and it goes without saying that improvements and design changes can be made without departing from the scope of the present invention.

In FIG. 1, a wafer support member 1 in which an internal electrode 3 serving as a plasma generating electrode and an internal electrode 4 serving as an electrostatic attracting electrode are embedded in a plate-shaped ceramic body 2 has been described as an example. The present invention is not limited to the structure alone, and can be applied to a wafer support member in which an internal electrode is a heater electrode and is used by applying a DC voltage. Support member provided with an internal electrode which forms an electrode for heating and an electrode for heater and an electrode for plasma generation, and a wafer support provided with three internal electrodes of an electrode for electrostatic attraction, an electrode for heater and an electrode for plasma generation Needless to say, it can be suitably used for members.

[0049]

EXAMPLE Here, a wafer support member 1 of the present invention shown in FIG. 1 and a conventional wafer support member 31 shown in FIG.
An experiment was conducted to determine whether or not there was conduction between the external terminals 5, 6, 35, and 36 due to ion migration when the silicon wafer was suction-held while being heated to a high temperature of 50 ° C.

In this experiment, the wafer support members 1, 31
Of the plate-shaped ceramic bodies 2 and 32 and the cylindrical bodies 7 and 8
Are formed of aluminum nitride ceramics having an AlN content of 99.9% by weight and a coefficient of thermal expansion of 5 × 10 ⁻⁶ / ° C., and are embedded in the plate-shaped ceramic bodies 2 and 32 as electrodes for plasma generation. The internal electrodes 3 and 33 and the internal electrodes 4 and 34 as electrodes for electrostatic adsorption were each formed of a tungsten film. However, the internal electrode 3 has a disk shape, the internal electrode 4 has the pattern shape shown in FIG. 3A, and the outer diameter of the plate-shaped ceramic bodies 2 and 32 is 200 m.
m.

The external terminals 5, 6, 35, 36 electrically connected to the internal electrodes 3, 4 have a thermal expansion coefficient of 4.
It is formed of an Fe-Ni-Co alloy at 7 × 10 ⁻⁶ / ° C., and is brazed and fixed to each of the plate-shaped ceramic bodies 2 and 32 using a Cu-Ag-Ti-based brazing material. The predetermined distance t between the external terminals 5 and 6 and the cylindrical bodies 7 and 8 was set to about 5 μm.

Then, these wafer support members 1 and 31
Is set in the vacuum processing chamber of the PVD apparatus, and the internal electrodes 3 serving as electrodes for plasma generation in the wafer support members 1 and 31 are set.
13.56 between the electrode 33 and the electrode 41 for plasma generation.
While supplying a fluorine gas in a state where plasma is generated by applying a high-frequency power of MHz, the wafer supporting members 1 and 31 are indirectly heated to 550 ° C. by a separately provided heater, so that the external terminals 6 and 36 are heated. Wafer W placed on the mounting surfaces 2a and 32a by applying a DC voltage of 250 V
Was fixed by adsorption for one hour, and an experiment was conducted to check whether there was conduction between the external terminals 5, 6, 35, and 36 due to ion migration.

As a result, the conventional wafer support member 31 does not include a cylindrical body that covers the external terminals 35 and 36.
Since the brazing material layer was exposed to the atmosphere, migration of Cu ions occurred between the external terminals 36 to form a Cu conductor layer, and it was not possible to develop an electrostatic attraction force after the experiment.

Also, migration of Cu ions was observed between the external terminal 35 electrically connected to the electrode for plasma generation and the external terminal 36 electrically connected to the electrode for electrostatic attraction.

On the other hand, the wafer support member 1 of the present invention
Although migration has been observed, the movement of Cu ions is prevented by the cylindrical members 7 and 8 which are in close contact with the plate-shaped ceramic body 2 and conduction between the external terminals 5 and 6 can be prevented. Even after the experiment, the electrostatic attraction force could be stably exhibited.

[0056]

As described above, according to the present invention, at least one internal electrode is provided in a plate-shaped ceramic body having a wafer mounting surface, and an external electrode electrically connected to the internal electrode is provided. In a wafer support member in which a terminal is implanted in the plate-shaped ceramic body using a brazing material containing silver and / or copper, a ceramic having a larger coefficient of thermal expansion than the external terminal is provided on an outer periphery of the external terminal. Ni or Ni alloy, or N
A cylindrical body made of a metal member coated with any one of i, Au, and Pt is attached, and the end of the cylindrical body is arranged at a position separated by a predetermined distance from the surface of the plate-shaped ceramic body. In a high-temperature atmosphere of 100 ° C. or more, the tubular body is thermally expanded more than the external terminals so as to be in airtight contact with the plate-shaped ceramic body. Even if the silver ions or copper ions of the material migrate due to migration, the movement can be prevented by the cylindrical body that is in close contact with the plate-shaped ceramic body. Can be kept.

Thus, when the internal electrode is an electrode for electrostatic attraction, a stable electrostatic attraction force is always exerted, and the wafer can be precisely attracted and fixed to the mounting surface, and the internal electrode is a heater electrode. In some cases, the wafer on the mounting surface can always be heated to a predetermined temperature, and when the internal electrode is a plasma generating electrode, plasma with a uniform density can always be generated. If the member is used for a film forming apparatus or an etching apparatus, a highly accurate film forming or etching process can be performed on a wafer.

According to the present invention, an annular groove is formed on the surface of the plate-shaped ceramic body at a position where the end of the cylindrical body is opposed to the end of the cylindrical body. Since it is installed at a position separated by a predetermined distance from the bottom surface, the contact area between the plate-shaped ceramic body and the cylindrical body can be increased and the airtightness can be increased, so that the progress of migration can be effectively prevented and Corrosion and abrasion of the brazing material layer and external terminals from corrosive gas such as halogen gas or plasma or plasma can also be effectively prevented.

[Brief description of the drawings]

FIG. 1A is a perspective view showing an example of a wafer support member of the present invention, and FIG. 1B is a sectional view taken along line XX of FIG.

2 (a) is a cross-sectional view of a main part of FIG. 1 (b) enlarged at room temperature, and FIG. 2 (b) is a cross-sectional view of a main part of FIG. 1 (b) enlarged under a high temperature atmosphere. .

3 (a) to 3 (c) are diagrams showing various pattern shapes of internal electrodes forming electrodes for electrostatic attraction. FIG.

FIG. 4 is an enlarged sectional view of a main part of another wafer support member of the present invention at room temperature.

FIG. 5A is a perspective view showing an example of a conventional wafer support member, and FIG. 5B is a sectional view taken along line YY of FIG.

[Explanation of symbols]

1, 31: wafer support member 2, 32: plate-shaped ceramic body 3, 33: internal electrode serving as an electrode for plasma generation 3a.
33b: mounting surface 3b, 33b: pilot hole 4, 34: internal electrode forming electrode for electrostatic attraction 5, 6, 35, 36: external terminal 7, 8: cylindrical body W:
Wafer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) H02N 13/00 H01L 21/302 BF term (Reference) 3C016 AA01 GA10 4K029 DA08 JA01 5F004 BB22 BB26 BB29 5F031 CA02 DA13 HA17 MA28 MA29 MA32 5F045 AA08 BB20 EB03 EB05 EK01 EM05

Claims (3)

[Claims] 1. A plate-shaped ceramic body having at least one internal electrode in a plate-shaped ceramic body having a mounting surface on which a wafer is mounted, and an external terminal electrically connected to the internal electrode is connected to the plate-shaped ceramic body. In a wafer supporting member implanted on the surface of a body using a brazing material containing silver and / or copper, a ceramic, Ni or Ni alloy having a larger coefficient of thermal expansion than the external terminal is provided around the external terminal. Alternatively, a cylindrical body made of a metal member coated with any of Ni, Au, and Pt is attached, and the end of the cylindrical body is arranged at a position separated by a predetermined distance from the surface of the plate-shaped ceramic body. A wafer support member characterized in that: 2. The wafer supporting member according to claim 1, wherein an annular groove is formed on a surface of the plate-shaped ceramic body at a position where an end of the cylindrical body is opposed. 3. The wafer support member according to claim 1, wherein the internal electrode is any one of an electrode for electrostatic attraction, an electrode for heater, and an electrode for plasma generation.